I wanted to know if this has any prerequisites like knowledge of server technologies, previous experience implementing them, any certifications etc. ?

What should one know/ do if they are planning for this certification to set a new career ?

I see plently of experts out here with experience implementing ITIL / ISO 20000. Could any of you guide us on important things we should know before pursuing this certification or challenges for which we should be prepared when we take this as career ?

You do not need specific technical knowledge, as the ITIL framework is not technology specific - the same basic approach for managing the provision of services, whatever the technology in use. However, for the Manager's exam you are expected to have at least 5 years experience, including as a manager. This is not verified, but it is hard to answer at the level required without this experience.

I did my Six Sigma Green Belt certification and have more than 5 years experience in ITeS-BPO industry providing technial support and managing team. Would you think this certification might help me with my career growth ?